An employee of the auction house Zisska and Lacher holds a photograph with the signature of Adolf Hitler and general Erich Ludendorff on the back side in Munich, southern Germany, April 20, 2017. A book and other Nazi memorabilias, will be auctioned on May 10, 2017. REUTERS/Michael Dalder

An employee of the auction house Zisska and Lacher holds a photograph with the signature of Adolf Hitler and general Erich Ludendorff on the back side in Munich, southern Germany, April 20, 2017. A book and other Nazi memorabilias, will be auctioned on May 10, 2017. REUTERS/Michael Dalder